1. Field of the Invention
The present invention is directed to a safety arrangement for a cable-supported component of a medical device, and in particular to such a safety arrangement which arrests the component and prevents displacement thereof in the event of a cable breakage.
2. Description of the Prior Art
German PS 196 35 236 discloses a weight counterbalance device, particularly for a medical radiographic device, wherein a spring, is connected to oppose rotation of a drum on which a cable is wound, so that the spring exerts a force on the cable, which force counteracts the weight of a component, connected to the cable, of a medical device. This equilibration device can be allocated to a telescoping column that is guided at the ceiling and has an X-radiator arranged at its lower end. The equilibration device also has a further spring element and a further cable that act on separate safety means, which prevent a displacement of the X-radiator if the primary spring or the primary cable breaks, so that the X-radiator does not unimpededly fall by gravity on an obstacle or in the worst case, so as to even hit a person. The safety means has detent pawls which engage the housing of the cable drum, for example, in the event of a breakage.
German PS 36 21 565 describes a vertically adjustable holding device with a base block that can be moved in a groove of a carrying arm for a device component, and with a means for fixing and releasing the base block in the groove. The means for fixing and releasing has two swivel arms that each have a brake shoe at their ends. At the other end, each swivel arm is freely pivotably connected to a shaft. A mechanical operating element that engages the shaft, in the form of a rocker arm or an adjustment bar, cooperates with the shaft such that it can be vertically displaced. The base block can be fixed or released in the groove by actuating the operating element to rotate the shaft, whereby the brake shoes are latched in the groove or are released.
German OS 23 52 836 describes a clamping device for fixing two machine parts that can be spatially displaced relative to one another. The clamping device has a number of prestressed clamping bodies. The clamping bodies cooperate with covering walls, which, when a force acts upon the clamping bodies, are pushed outwardly in order to achieve a latching of the clamping device, in a groove, for example. The clamping device can be fashioned in a self-locking manner.
An object of the present invention is to provide a safety arrangement for a cable-supported component of a medical device that can be adjusted via a cart at a column such that, in a reliable manner, it prevents displacement of the cart when the cable and/or a spring breaks, (if present) for example.
The above object is achieved in accordance with the principles of the present invention in a medical device having a column in which a rider block is movable, and at least one clamping lever connected to a cable, the cable supporting a medical device component at an opposite end and the clamping lever being movably mounted at the rider block, so that when a force acts on the cable the rider block is freely movable within the column so as to allow adjustment of the position of the cable-supported component, and wherein the clamping lever is mounted to the rider block so as to prevent displacement of the rider block relative to the column when the force acting on the cable is reduced or removed.
An advantage of the invention is that a force acts on at least one clamping lever that is adjustably at the cart via a cable, for example, so that given action of the force, the cart is free for purposes of adjusting along the column and whereby, given reduction of the force, the clamping lever is automatically deployed such that it blocks the displacement of the cart relative to the column. Such a safety arrangement is uncomplicated in the construction, since only one clamping lever is provided via which a displacement of the cart can be blocked. Besides, the clamping lever is effective regardless of whether the cable or spring used for purposes of compensating the weight of the component breaks. Therefore, double safety measures need not be provided, as in the prior art, since the safety arrangement is self-locking.
It is especially advantageous when the force acts on the cable at the clamping lever and when the force originates from an equilibration arrangement for compensating the weight of the component and the cart. Therefore, a safety arrangement is created that blocks displacement of the cart via a clamping lever given no action of the force of the equilibration arrangement, as occurs when the cable breaks, for example.
It is also advantageous for the force to be conducted to the clamping lever via a manually operated element, since the user, by applying a force, thus can displace the cart and the component, and a blocking of the displaceability of the cart ensues via the manually operable element when a force is present.
It is advantageous for the clamping lever to effect blocking of displacement of the cart in a spring-weighted manner, since the response of the clamping lever can be adjusted depending on the spring loading (biasing).
In an embodiment wherein two clamping levers are provided which engages the cable, a symmetrical blocking of displacement of the cart ensues and the forces of the blocking are also distributed via both clamping levers.
For achieving a lever action, it is advantageous for each clamping lever to be pivoted around respective pivot axles, with the cable engaging a cable arm or clamping arm of the clamping lever.
In a further embodiment the clamping levers have a common spring element.
A compact structure of the safety arrangement in an embodiment wherein from the clamping arm and the cable arm of the clamping levers forming an angle toward one another.
Here, it is also advantageous for the clamping arms have a common pivot axle, around which they can be pivoted.